Radial force


  I am a beginner in LAMMPS simulation. I have a system of particles which
form a circular ring by their connectivity. Now I wan to apply outward
radial force to each of the particles so that the shape of the ring
remains the same. I am approaching with fix addforce commands where i
have defined per atom force components by variable commands. But the
problem is, though the mod value of the force is working as per demand
but its direction is no more radially outward as its always applying in
the positive direction in X & Y . How can it be resolved?

Thanks in advance.


I guess this can be easily simulated considering hydrostatic force (i.e., isotropic/anisotropic) etc.

Nobody can tell without knowing your input. Most likely your math is wrong.